Automatic control for hydraulic pumps



F. E. STEVENSON.

AUTOMATIC CONTROL FOR HYDRAULIC PUMPS.

APPLICATION FILED MAR. II, 1921- Patented Apr. 11, 1922;

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F. E. STEVENSON. AUTOMATIC CONTROL FOR HYDRAULIC PUMPS.

APPU CATlON HLED MAR. H, 1 92I- v 1,412 ()69 I v Patented Apr. 11, 1922.

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" llllflllllm enibr Patented Apr.- 11, 1922.

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AUTOMATIC CONTROL FOR HYDRAULIC PUMPS.

APPLICATION FILED MAR. H, 1'92!- F. E. STEVENSON. AUTOMAHOCONTROL FOR HYDRAULIC PUMPS.

APPLICATION FILED MAR.1I, 1921- I 1,412,069, Patented Apr. 11, 1922.

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1 K 5 :EFFK 5v UNITED STATES PATENT OFFICE.

' FRANCIS n; STEVENSON, or MOUNT GILEAD, OHIO, ASSIGNOR TO THE HYDRAULIC rnnss MANUFACTURING COMPANY, on MOUNT GILEAJ), O-HIQ AUTOIATIC CONTROL FOR- HYDRAULIC PUMPS.

Specification of Letters Patent. Patented A 11 1922 Application filed March 11, 1921. Serial No. 451,433.

To all whom it may concern.

Be it known that I, FRANCIS E. STEVEN- soN, a citizen of the United States, residing at Mount Gilead,'in the county of Morrow and State of Ohio, ha-ve'invented certain new and useful Improvements in Automatic Controls for Hydraulic Pumps, of which the following is a specification.

This invention relates to the control of pumps working at two pressures for supplying hydraulic presses and other mechanism to be operated by liquid under pressure, and the object of the invention is to provide meanswhereby when a'low-pressure pump is operated to its full capacity a high-pressure pump may be automatically brought into use and when the high-pressure pump has reached its maximum effect, the operation of the pumps may be suspended.

It has heretofore been common to actuate a hydraulic press at first by a low-pressure, quick-acting pump and then to brlng into operation a more slowly acting but more powerful high-pressure pump, and my inventionis especially intended for use in such a system. -My special object isto provide means whereby when the low-pressure pump has reached the limit of its capacity in the pressing operation the remainder of the work may be performed by the high-pressure pump which is automatically brought into service as soon as the low-pressure pump ceases to operate.

Preferably I embody my invention in a pipe and press system in which a single lowpressure pump and a single high-pressure pump is used, but a plurality of each of said pumps may be employed if necessary.

In carrying out my invention, where one high-pressure pump and one low-pressure pump is employed, I connect the valve chests of the two pumps with a source of motive fluid, such as steam, and I connect the lowpressure pump with a ipe leading to the press or place of use. n this pipe a check valve is installed which prevents back pressure. The high-pressure pump is pipeconnected with the before mentioned pipe between the press and the check valve. In the pipe conveying motive fluid to the high. pressure pumping engine, a valve is installed which controls the supply to the high pressure engine. This valve is normally, or during the first part of the operation, closed, but it 1s connected to and operated by a control valve which autpmatically opens and Closes pump goes out of servlce.

it under certain conditions. Said control valve comprises two valve members which are operated by motive fluid conveyed-by p pe connections from the press supply pipes, one of said valves being operated by fluid taken from the press supply pipe between the check valve and the low-pressure englne and the other valve being operated by fiuld taken from the press supply pipe leadmg from the high pressure engine. The details of construction of the control valve will be hereinafter described. When starting the operation, the low-pressure pump is first brought into service. This engine operates quickly to partially perform the pressing operation. As soon as the maximum effect of the low-pressure pump is reached, the check valve is automatically closed and the control valve is operated to open the valve in the supply pipe of the high-pressure pump. This pump is then actuated to complete the operation, while the low-pressure As soon as the operation of the press is completed, that is after the predetermined pressure is obtained, the control valve is actuated to close the fluid pressure supply to the high-pressure pump which then ceases to operate, and as the low-pressure pump cannot operate against the pressure obtained in the hydraulic press, the low-pressure pump also remains out of operation.

My improvements are illustrated in the accompanying drawings, in which Figure 1- shows diagrammatically a system of pumping engines, pipes and control valves with my improvements applied.

The remaining figures are on an enlarged scale.

Figure 2 is a sectional view of the control valve mechanism.

Figure 3 shows a side elevation thereof.

Figure 4 is a plan view of a part of the control valve mechanism with the top plate of the valve chest removed. W

Figure 5 shows a section on the line 5 5 of Figure 4.

Figure 6 shows a section on the line 66 of Figure 4, and

Figure 7 shows a section on the line 7'7 of the same figure.

Figure8 is a perspective view of one of the valve members, and

Figure 9 is a perspective view of the other valve member.

Figure 10 is a sectional view of the valve which controls the supply of the motive fluid to the high-pressure pumping engine.

Figures 11, 12 and 13 show diagrammatically the operation of the control valve mechanism under different conditions.

Referring to Figure 1 of the drawings, I

have shown a low-pressure pumping engine A and a high-pressure pumping engine B.

The low-pressure pump is connected by a pe C to a hydraulic press (not shown) or to other place for use. The press supply pipe G contains a check valve 0 opening toward the press, but which may be closed automatlcally when the pressure in the pipe on the press side exceeds the pressure on the pump side of the valve. The high-pressure pumping engine is connected to the press supply pipe by a pipe E. Steam or other motive fluid is supplled to the low-pressure pumping engine by a pipe F containing a hand operated valve G and the motive fluid is supplied to the high-pressure pumping engme by a pipe H containing a hand op.- erated valve h and also an automatic valve K actuated by fluid pressure controlled by the control valve M. The valve K isconnected by pipes a: and M and said control va ve is connected by a pipe 2 to the supply pipe H. The control valve is connected by a pipe 0 tothe pipe B :leading from the high-pressure pump and by a piper to the press supply pipe between the valyekc and the low-pressure engine. Any suitable means may be employed for feeding the pumps with hydraulic fluid.

The automatic valve K in the supply pipe L is preferably a quick actingbalanced pressure conveyed to it by the pipes 0 and 1". I

Two valve members m, .m are employed 1n the control valve mechanism and these valve members operate in a valve chest m having a removable top plate m The valve' chamber is permanently connected with the steam or other supply of motive fluid by a the pipe 2, and said valve chamber is connected by'pipe w to one end of the cylinder k of the valve K and by the pipe 3 to the other end of said cylinder. The valve chest is also connected by a pipe o with the exhaust pipe W of the two pumping engines. The valves m, m operate on valve seats n,'n,' being held to their seats by 'set screws n The valve 'm, is recessed onits under side and fits the valve seat 1 and the valve m is similarly recessed and fits the seat nT -Theivalve m is formed with recesses m, m and the valve m. is formed nuts 41 ,41 to the control valve high-pressure engine which causes a pressure to be lmp'arted in the'hy raulic,

similar recesses m", m. The valve m is also formed with an opening 11?) WhlCll extends through it for the passage of motive fluid from the valve chest to the passages in the valve seat which communicate wlth the pipes or conduits-m, y, z and w.

The metal block on which the valve seats are located is formed with various channels which are shown in the drawings and which will be hereinafter described.

The valve member on is connected by a rod P with a cross-head 'p 'to which it is firmly secured and the valve member 'm/ is similarly connected by a rod P to a cross-head 17'. Each cross head carries a piston or plunger S, S operating in chambers T, T to which hydraulic pressure is admitted through the pipes o and r. The chambers T, T are formed in'cylinders attached to a block U secured to a frame U towhich the valve chest m is also secured. Through the block U extend rods V, V which pass throu h sleeves 'v, v interposed between the block U' and the cross-heads p, p", At their upper ends the rods V V v The rods V, V extend through the block U and are formed with shoulders at. The rods V, V, are threaded at their lower ends and carry adjusting nuts 6, 6' arranged outside the cross-heads d, d through which the rods V, V extend. Between the cross-heads d, d and the block U are interposed coiled springs -e, e. adjusting thenuts b, b, '0 'v the tenslon of the springs may be; varied. The valve members m, m, it will be observed are moved in one direction by fluid pressure and in the opposite direction by the sprin e, e. The shoulders w .on the rods V, limit the movement of the valves in one direction, while the movement of the valves in the opposite direction are limited by the sleeves 42, 22. The plungers S, S. are of different sizes as shown, and they operate through suitable packing as indicated.

In the pressing operation the valves G and h are opened and steam or other motive carry adj usting fluid is admitted to the lowressure pumping engine. The supply 0 steam to the high-pressure um is at this time arrested by the valve ydraulic pressure 1s supplied to the press through the pipe C by means of the low-pressure pumping enginewhich is quickly operated to partially comress the material being operated upon. en the resistance of the compressed ma terial has reached a certain stage, the pres sure is conveyed through the pipe 1' to the control valve M and the valve member m" is so 0 erated as to automatically open the valve and admit flllld pressure to the ea r press. This pressure overbalances the pressure of the IQw-p es ure Pumpi g eng n and causes the check valve 0 to close. When the maximum or predetermined pressure is obtained, the pressure accumulates in the pipe E and is conveyed through the relatively small or pilot pipe 0. to the control valve M, and the valve m is operated to open connection between the valve chest and the pipe 00 and'fluid is conveyed by said pipe at to the valve K and the valve is closed so that the high-pressure engine is stopped. Inasmuch as the low-pressure pumping engine cannot overcome the pressure in the hydraulic press, said low pressure engine is also prevented from operating. Choking devices of Well known construction may be installed in the pipes o and 7' as indicated at X and Y to prevent sudden and violent movements in the control valve and any form of speed regulator may be applied to the low-pressure pump to prevent it from-racing. The manner in which the fluid pressure is passed through the control valve is illustrated diagrammatically in Figures 11, 12 and 13.

Figure 11 shows the position of the valve members when the high-pressure pumping engine is idle and the low-pressure pump is in operation. At this time the piston 70 is in position to hold the valve is closed. Steam or the like from 2 enters the valve chest, passes through the hole m in the valve member m and through the channel 9 to the valve m, and then through the pipe m to the cylinder I0 and the valve is is kept closed, and therefore, the high-pressure pumping engine is not operated. The opposite end of the cylinder 10 is connected by pipe y to the exhaust w in the manner indicated by the arrows.

Figure 12 shows the position of the valve mechanism when the low-pressure engine has reached the limit of its capacity. At this time fluid pressure passes through the pipe 7* and the valve m is shifted. Steam or the like entering at 2 passes through the hole m in the valve member m and through the channel to the pipe g and through this pipe to the cylinder h The valve 7' is thus opened and the high-pressure engine is put in operation.

In F igure' 13 the position of the valves is indicated when the high-pressure engine has reached the limit of its capacity. Steam or the like enters at 2, passes through the hole m in the valve m,"and through the channel w to the pipe :1: which conveys fluid to the cylinder k and the valve k is closed. Thereafter both pumping engines are held out of operation and the compression operation is completed.

I have shown conventional forms of high and -low pressure pumping engines and many parts of the invention illustrated are shown conventionally and diagrammatically. i

low-pressure engine.

2. A system of control for hydraulic pumps, comprising a low-pressure pump, a

high-pressure pump, a press supply pipe with which they are connected, a valve for controlling the supply of fluid pressure to the high-pressure pump, and a valve for opening and closing said high-pressure supply valve operated successively by fluid pressure supplied by the low-pressure and high-pressure engines.

A system of control for hydraulic pumps, comprising a low-pressure pump, a high-pressure pump, a press supply pipe with which they are connected, a valve for controlling the supply of fluid pressure to the high-pressure pump, and a valve for controlling said fluid pressure supply valve operated by fluid pressure taken from the press supply pipe.

system. of control for hydraulic pumps, comprising a low-pressure pump, a high-pressure pump, a press supply pipe with which they are connected, a valve for controlling the supply of fluid pressure to the high-pressure pump, and a valve for controlling said fluid pressure supply valved closed by pressure taken from the highpressure engine.

5. A system of control for hydraulic pumps, comprising a low-pressure pump, a high-pressure pump, a press supply pipe with which they are connected, a valve for controlling the supply of fluid pressure to the high-pressure pump, a valve controlling the opening of said fluid pressure valve op- 110 .erated by fluid pressure taken from the lowpressure engine, and a valve for controlling the closing of said fluid pressure admission valve operated by fluid'taken from the highpressure engine.

6. A system of control for hydraulic pumps, comprising a low-pressure pump, a high-pressure pump, a press supply pipe with which they are connected, a valve for controlling the supply of fluid pressure to the high-pressure pump, and a valve for controlling said fluid pressure supply valve, comprising a valve chest, valve members enclosed therein, pistons with which the valve members are connected and which are operated in one direction by fluid pressure from the pumps, and springs for moving the pistons and valves in the opposite direction.

7. A system of control for hydraulic 1 haust of fluid from the fluid pressure supply to the fluid pressure supply valve, pistons connected with said valve members,

and connections between one of said pistons 15 and the low-pressure pump, and connections between the other piston and the high pressure pump.

In testimony whereof, I have hereunto subscribed my name.

FRANCIS E. STEVENSON. 

